This invention relates generally to a bearing and lubrication system for a rotating shaft, and more particularly to systems of the type employing oil rings to deliver a lubricant from a supply thereof to a bearing assembly.
Rotating machinery such as gas or steam powered turbines typically include a power shaft, one or more sleeve or journal bearing assemblies to rotatably support the shaft, and one or more thrust bearing assemblies to limit axial movement of the shaft. Lubricant must be supplied to these bearing assemblies, and often the bearing assemblies of a rotating machinery are spaced from each other and a separate lubrication system is provided for each bearing assembly. Many lubrication systems are well known in the art, and one common type of system includes an oil ring or rings arranged within a bearing assembly so as to encircle the power shaft. The oil ring has a diameter greater than the diameter of the shaft, and the ring is positioned above a pool of lubricant so that at least a portion of the circumference of the ring is submerged within the lubricant. Rotation of the power shaft within the bearing assemblies causes rotation of the oil ring. As the oil ring rotates and travels through the supply of lubricant, lubricant clings to the oil ring and is carried upward thereby. The inner surface of the oil ring is usually provided with grooves or the like to increase the amount of oil which clings to the ring and is carried upward thereby. Oil carried upward by the inner surfaces of the oil ring is deposited on and migrates along the bearing surfaces of a bearing assembly, lubricating these surfaces. Oil carried upward by the outside surfaces of the oil ring is thrown radially outward by the ring toward the shell or casing of the machinery, and this oil generally flows down the inside surface of the shell, returning to the lubricant pool.
As the lubricant flows along surfaces of the shaft and associated bearing assemblies, the lubricant is heated by friction between these surfaces. Often, the lubricant is cooled by being circulated through a heat exchanger. In this case, a lubricant pump is frequently employed to circulate the lubricant between the supply thereof and the heat exchanger. This pump and its associated piping increase the cost and complexity of manufacturing, operating, and maintaining the rotatable machinery.